Electrical energy delivery tissue site validation

ABSTRACT

Electrical energy delivery tissue site validation systems and methods can determine an indication of a tissue type at a tissue site. This information can be used to enable or inhibit electrical energy delivery to the tissue site. The tissue type at the tissue site can be determined such as by delivering a test electrical energy and sensing a responsive electrical energy. An electrical connectivity to the tissue site can also be determined, such as by using a sensed intrinsic electrical signal at the tissue site. Tissue type information may be communicated externally, such as to allow user confirmation or override of the determined indication of tissue type at the tissue site, such as by a physician, user, or other operator.

CLAIM OF PRIORITY

This application is a continuation of and claims the benefit of priorityunder 35 U.S.C. §120 to David Ternes, U.S. patent application Ser. No.13/237,491, entitled “Electrical Energy Delivery Tissue SiteValidation,” filed on Sep. 20, 2011, now issued as U.S. Pat. No.8,676,307, which is a continuation of and claims the benefit of priorityunder 35 U.S.C. §120 to David Ternes, U.S. patent application Ser. No.11/549,439, entitled “Electrical Energy Delivery Tissue SiteValidation,” filed on Oct. 13, 2006, now issued as U.S. Pat. No.8,036,739, each of which is hereby incorporated by reference herein inits entirety.

TECHNICAL FIELD

This patent document pertains generally to implantable medical devices,and more particularly, but not by way of limitation, to electricalenergy delivery tissue site validation.

BACKGROUND

Certain patients exhibit a need for cardiac or neural stimulation, suchas by using an implantable medical device. When such a need exists,cardiac tissue can receive cardiac electrostimulation. Such stimulationcan evoke a resulting heart contraction, and can be used to maintain arate of heart contractions that will meet a patient's metabolic need forcardiac output, or to spatially coordinate heart contractions such as toimprove the heart's pumping efficiency. Similarly, non-cardiac neuraltissue can receive neural stimulation, e.g., neurostimulation energy.Neurostimulation may be used to affect the autonomic balance between thesympathetic nervous system (which tends to speed up certain metabolicprocesses) and the parasympathetic nervous system (which tends to slowdown certain metabolic processes). Some patients may benefit from bothcardiac and neural stimulation.

OVERVIEW

The present inventors have recognized that, among other things, it maybe undesirable to deliver electrical energy to tissue that was not meantto receive the delivered electrical energy. For example, delivery of acardiac pacing or shocking energy to a non-cardiac tissue, such as anerve, might damage or otherwise impair the non-cardiac tissue. Even ifdelivery of a cardiac pacing or shocking energy to a non-cardiac tissue,such as a vein wall, does not cause damage, it might not provide theintended benefit of the cardiac pacing or shocking energy. In a similarvein, delivery of a neural stimulation energy to a cardiac tissue mightdamage or otherwise impair the cardiac tissue, or may inducepro-arrhythmic conditions. Thus, the present inventors have recognized,among other things, an unmet need for automatic electrical energydelivery tissue site validation for implantable medical devices.

In certain examples, electrical energy delivery tissue site validationsystems and methods can determine an indication of a tissue type at atissue site. This information can be used to enable or inhibitelectrical energy delivery to the tissue site. The tissue type at thetissue site can be determined such as by delivering a test electricalenergy and sensing a responsive electrical energy. An electricalconnectivity to the tissue site can also be determined, such as by usinga sensed intrinsic electrical signal at the tissue site. Tissue typeinformation may be communicated externally, such as to allow userconfirmation or override of the determined indication of tissue type atthe tissue site, such as by a physician, user, or other operator.

In Example 1, a system includes an implantable medical device. Theimplantable medical device includes an electrical energy deliverycircuit. The implantable medical device also includes an intrinsicelectrical signal sensing circuit. The implantable medical device alsoincludes at least one terminal, configured to couple the electricalenergy delivery circuit and the intrinsic electrical signal sensingcircuit to at least one tissue site. The implantable medical device alsoincludes a validation module, coupled to the electrical energy deliverycircuit and the intrinsic electrical signal sensing circuit, wherein thevalidation module is configured to determine at least one indication ofa tissue type at the at least one tissue site using an intrinsicelectrical signal received from the intrinsic electrical signal sensingcircuit, wherein the validation module is configured to automaticallyenable or inhibit electrical energy delivery by the electrical energydelivery circuit to the at least one tissue site using the at least oneindication of the tissue type.

In Example 2, the intrinsic electrical signal sensing circuit of Example1 is optionally configured to sense at least one intrinsic cardiacsignal.

In Example 3, the intrinsic electrical signal sensing circuit ofExamples 1-2 is optionally configured to sense at least one intrinsicneural

In Example 4, the validation module of Examples 1-3 is optionallyconfigured to distinguish between a cardiac tissue site and a neuraltissue site.

In Example 5, the system of Examples 1-4 optionally includes at leastone lead, configured to couple the at least one terminal to the at leastone tissue site, wherein the at least one lead comprises at least oneelectrode.

In Example 6, the at least one lead of Examples 1-5 optionally includesmultiple electrodes, wherein at least one electrode is configured tocontact a cardiac tissue site to provide a pacing energy, and wherein atleast one electrode is configured to contact a neural tissue site toprovide a neurostimulation energy.

In Example 7, the validation module of Examples 1-6 is optionallyconfigured to automatically enable or inhibit electrical energy deliveryat multiple tissue sites.

In Example 8, the validation module of Examples 1-7 optionally includesa user confirmation or override, wherein the user confirmation oroverride is configured to confirm or override the validation moduleprior to automatically enabling or inhibiting the delivery of electricalenergy.

In Example 9, the electrical energy delivery circuit of Examples 1-8 isoptionally configured to deliver a pacing energy.

In Example 10, the electrical energy delivery circuit of Examples 1-9 isoptionally configured to deliver a neurostimulation energy.

In Example 11, the system of Examples 1-10 optionally includesnotification module, coupled to the validation module, wherein thenotification module is configured to communicate information of thetissue type at the tissue site to an external device.

In Example 12, the electrical energy delivery circuit of Examples 1-11is optionally configured to deliver a test electrical energy to the atleast one tissue site, wherein the intrinsic electrical signal sensingcircuit is configured to detect an intrinsic response energy in responseto the test electrical energy, and wherein the validation module isconfigured to determine at least one indication of a tissue type at theat least one tissue site the intrinsic response energy.

In Example 13, the test electrical energy of Example 1-12 optionallyincludes a pacing energy.

In Example 14, the test electrical energy of Examples 1-13 optionallyincludes a neurostimulation energy.

In Example 15, the test electrical energy of Examples 1-14 optionallyincludes a test electrical energy that is safe for neural tissue andsufficient to trigger a cardiac response.

In Example 16, the system of Examples 1-15 optionally includes aconnectivity module, coupled to the electrical energy delivery circuitand the intrinsic electrical signal sensing circuit, wherein theconnectivity module is configured to detect an electrical connectivityto the at least one tissue site, and wherein the connectivity module isconfigured to automatically enable or inhibit electrical energy deliveryby the electrical energy delivery circuit to the at least one tissuesite using the detected electrical connectivity to the at least onetissue site.

In Example 17, a system includes means for sensing at least oneintrinsic electrical signal at a corresponding at least one tissue site,such as by using at least one terminal to couple the system to the atleast one tissue site. The system also includes means for determining atleast one indication of a tissue type at the at least one tissue siteusing the at least one intrinsic electrical signal, such as by using avalidation module to determine at least one indication of a tissue typeat the at least one tissue site using the at least one intrinsicelectrical signal sensed at the corresponding at least one tissue site.The system also includes means for automatically enabling or inhibitingelectrical energy delivery to the at least one tissue site using the atleast one indication of the tissue type, such as by using the validationmodule to automatically enable or inhibit electrical energy delivery byan electrical energy delivery circuit to the at least one tissue siteusing the at least one indication of the tissue type at the at least onetissue site.

In Example 18, a method includes sensing at least one intrinsicelectrical signal at a corresponding at least one tissue site. Themethod also includes determining at least one indication of a tissuetype at the at least one tissue site using the at least one intrinsicelectrical signal. The method also includes automatically enabling orinhibiting electrical energy deliver to the at least one tissue siteusing the at least one indication of the tissue type.

In Example 19, the sensing of Example 18 optionally includes sensing anintrinsic cardiac signal.

In Example 20, the sensing of Examples 18-19 optionally includes sensingan intrinsic neural signal that is different from an intrinsic cardiacsignal.

In Example 21, the sensing at least one intrinsic electrical signal ofExamples 18-20 optionally includes using at least one electrode to senseat least one intrinsic cardiac signal and at least one electrode tosense at least one intrinsic neural signal, wherein the multipleelectrodes are coupled to a single lead.

In Example 22, the automatically enabling or inhibiting electricalenergy delivery of Examples 18-21 optionally includes automaticallyenabling or inhibiting at multiple tissue sites.

In Example 23, the automatically enabling or inhibiting of Examples18-22 optionally includes obtaining user confirmation or override beforethe enabling or inhibiting.

In Example 24, the delivering an electrical energy of Examples 18-23optionally includes delivering a pacing energy.

In Example 25, the delivering an electrical energy of Examples 18-24optionally includes delivering a neurostimulation energy.

In Example 26, the determining at least one indication of a tissue typeat the at least one tissue site of Examples 18-25 optionally includesdelivering a test electrical energy to the at least one tissue site anddetecting a test electrical signal response to the delivering of thetest electrical energy to the at least one tissue site.

In Example 27, the delivering a test electrical energy of Examples 18-26optionally includes delivering a pacing energy.

In Example 28, the delivering a test electrical energy of Examples 18-27optionally includes delivering a neurostimulation energy.

In Example 29, the method of Examples 18-28 optionally includescommunicating to an external device information about the tissue type atthe tissue site.

In Example 30, the method of Examples 18-29 optionally includedetermining an electrical connectivity to the at least one tissue siteand automatically enabling or inhibiting electrical energy delivery tothe at least one tissue site using the determined electricalconnectivity to the at least one tissue site.

This overview is intended to provide an overview of the subject matterof the present patent application. It is not intended to provide anexclusive or exhaustive explanation of the invention. The detaileddescription is included to provide further information about the subjectmatter of the present patent application.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsdescribe substantially similar components throughout the several views.Like numerals having different letter suffixes represent differentinstances of substantially similar components. The drawings illustrategenerally, by way of example, but not by way of limitation, variousembodiments discussed in the present document.

FIG. 1 illustrates generally an example of a system including animplantable medical device, which includes an electrical energy deliverycircuit, an intrinsic electrical signal sensing circuit, a terminal, anda validation module.

FIG. 2A illustrates generally an example of a system including animplantable device and more than one terminal for both cardiac andneural stimulation.

FIG. 2B illustrates generally an example of a system including animplantable device and more than one terminal for both cardiac andneural stimulation.

FIG. 3 illustrates generally an example of a system including a userconfirmation/override.

FIG. 4 illustrates generally an example of a system including animplantable medical device and an external device, the implantablemedical device including an electronic energy delivery circuit, anintrinsic electrical signal sensing circuit, a terminal, a validationmodule, and a notification module.

FIG. 5 illustrates generally an example of a system including animplantable medical device, the implantable medical device including anelectrical energy delivery circuit, an intrinsic electrical signalsensing circuit, a terminal, a validation module, and a connectivitymodule.

FIG. 6 illustrates generally an example of a method includingautomatically enabling or inhibiting electrical energy delivery to atissue site using a determined indication of the tissue type, where thetissue type is determined using a sensed intrinsic electrical signals atthe tissue site.

FIG. 7 illustrates generally an example of a method includingdetermining an indication of tissue type, which includes delivering atest electrical energy to the tissue site and detecting a response tothe delivered test electrical energy.

FIG. 8 illustrates generally an example of a method including obtaininga user confirmation/override.

FIG. 9 illustrates generally an example of a method includingcommunicating an indication of tissue type to an external device.

FIG. 10 illustrates generally an example of a method includingautomatically enabling or inhibiting electrical energy delivery to atissue site using a determined electrical connectivity to the tissuetype, where the connectivity is determined using a sensed intrinsicelectrical signals at the tissue site.

FIG. 11 illustrates generally an example of a method including enablinga pacing energy and inhibiting a neurostimulation energy if an intrinsiccardiac signal is present, inhibiting a pacing energy if an intrinsiccardiac signal is not present, enabling a neurostimulation energy andinhibiting a pacing energy if an intrinsic neural signal is present, andinhibiting a neurostimulation energy if an intrinsic neural signal isnot present.

DETAILED DESCRIPTION

The following detailed description includes references to theaccompanying drawings, which form a part of the detailed description.The drawings show, by way of illustration, specific embodiments in whichthe invention may be practiced. These embodiments, which are alsoreferred to herein as “examples,” are described in enough detail toenable those skilled in the art to practice the invention. Theembodiments may be combined, other embodiments may be utilized, orstructural, logical and electrical changes may be made without departingfrom the scope of the present invention. The following detaileddescription is, therefore, not to be taken in a limiting sense, and thescope of the present invention is defined by the appended claims andtheir equivalents.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one. In this document, the term“or” is used to refer to a nonexclusive or, unless otherwise indicated.Furthermore, all publications, patents, and patent documents referred toin this document are incorporated by reference herein in their entirety,as though individually incorporated by reference. In the event ofinconsistent usages between this document and those documents soincorporated by reference, the usage in the incorporated reference(s)should be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

FIG. 1 is a block diagram illustrating generally an example of portionsof a system 100 including an implantable medical device 105, whichincludes an electrical energy delivery circuit 115, an intrinsicelectrical signal sensing circuit 125, a terminal 135, and a validationmodule 145.

In this example, one or more terminals 135 are configured to couple theelectrical energy delivery circuit 115 and the intrinsic electricalsignal sensing circuit 125 to at least one tissue site in the body. Inother examples, the terminal 135 can include a single terminal, or morethan one terminal, to couple one or both of the electrical energydelivery circuit 115 and the intrinsic electrical signal sensing circuit125 to a single tissue site, or to more than one tissue site, in thebody. Thus, a single terminal can connect to an electrode to contact asingle tissue site, or to different electrodes respectively located atmore than one tissue site, or more than one terminal can connect to asingle tissue site or more than one tissue site.

In certain examples, the terminal 135 connects the implantable medicaldevice 105 to at least one tissue site in the body using at least oneleadwire or catheter (referred to as a “lead”), where each lead includesone or more electrodes to contact the at least one tissue site. In otherexamples, the terminal 135 can include any electrical connector betweenthe implantable medical device 105 and an electrical connection to thetissue site.

In the example of FIG. 1, the implantable medical device 105 can includea cardiac stimulator, such as a pacer or cardiac resynchronizationtherapy (CRT) device to deliver a pacing or resynchronization energy toa cardiac tissue, or a neural stimulator, such as a vagal nervestimulator (VNS) device to deliver a neurostimulation energy to anon-cardiac neural tissue, or both. In certain examples, the implantablemedical device 105 can provide a shocking energy, such as adefibrillation energy. The implantable medical device 105 can includeany device configured to deliver an electrical energy to a cardiactissue, any device configured to deliver an electrical energy to aneural tissue, or any device configured to delivery an electrical energyto a cardiac tissue as well as a neural tissue.

The intrinsic electrical signal sensing circuit 125 is configured toreceive an intrinsic electrical signal from a tissue site in the body.An intrinsic electrical signal can also include an electricalcharacteristic of a tissue site in the body, e.g., the electricalimpedance at a tissue site. In certain examples, the intrinsicelectrical signal sensing circuit 125 is configured to receive more thanone intrinsic electrical signal from one or more tissue sites in thebody.

In the example of FIG. 1, the validation module 145 is coupled to theelectrical energy delivery circuit 115 and the intrinsic electricalsignal sensing circuit 125. In an example, the validation module 145 canbe included in the implantable medical device 105. In other examples,the validation module 145 can be an implantable component external tothe implantable medical device 105, or can be an external component. Thevalidation module 145 generally determines an indication of a tissuetype at the tissue site to which the terminal 135 is coupled. In oneexample, the validation module 145 receives an intrinsic electricalsignal from the intrinsic electrical signal sensing circuit 125 and usesthe intrinsic electrical signal to determine the indication of thetissue type at the tissue site. In certain examples, the validationmodule 145, upon determining the indication of the tissue type at thetissue site, enables or inhibits electrical energy delivery to thetissue site using the determined indication of the tissue type at thetissue site.

FIGS. 2A and 2B are block diagrams illustrating generally an example ofa system 200 including an implantable medical device 205. In theseexamples, the implantable medical device 205 can include a header 250having more than one terminal, e.g., a first terminal 255 and a secondterminal 260, such as to permit both cardiac and neural stimulation.Examples of the implantable medical device 205 include any devicecapable of providing neural or cardiac stimulation.

In certain examples, the implantable medical device 205 includes ahermitically-sealed or similar housing 245 coupled to the header 250.The header 250 can include one or more than one terminal, e.g., thefirst terminal 255 or the second terminal 260.

In the example of FIGS. 2A and 28, the system 200 includes a first lead215 coupled to the first terminal 255. In certain examples, the firstlead 215 is configured to provide stimulation to the heart 210 or sensean intrinsic cardiac signal of the heart 210. An intrinsic cardiacsignal can include any signal indicative of cardiac activity, e.g., aninternal electrocardiogram signal (ECG). In certain examples, the firstlead 215 can include a single electrode, e.g., a tip electrode 225, ormore than one electrode, e.g., the tip electrode 225 and a ringelectrode 220. In other examples, the housing 245 can include anelectrode, such as a “case” or a “can” electrode, or the header 250 caninclude an electrode, such as an indifferent electrode.

In this example, system 200 further includes a second lead 235 coupledto the second terminal 260. In certain examples, the second lead 235 isconfigured to provide stimulation to a nerve, e.g., the vagal nerve, orto sense an intrinsic neural signal. An intrinsic neural signal can beany signal indicative of neural activity. In other examples, the secondlead 235 can include a portion configured to be located in the jugularvein 230 and can include a distal end 240, which can include a nervestimulation electrode located at or near the distal end 240. In certainexamples, the second lead 235 can include a bend 236 associated with thelocation of the second lead 235, such as in the jugular vein 230, in yetother examples, the second lead 235 can include a cuff electrode, whichcan be configured to provide stimulation to a nerve or to sense anintrinsic neural signal.

In certain examples, the system 200 includes a single terminal, e.g.,the first terminal 255, configured to either provide stimulation to theheart 210 or to sense an intrinsic cardiac signal of the heart 210, orto provide stimulation to a nerve, e.g., the vagal nerve, or to sense anintrinsic neural signal.

FIG. 3 is a block diagram illustrating generally an example of avalidation module 145 including a user confirmation/override 146. Incertain examples, the validation module 145 can include the userconfirmation/override 146, or be coupled to the userconfirmation/override 146. In one example, the userconfirmation/override 146 is configured to allow a physician, user, orother operator, to either confirm or override the tissue typeautomatically determined by the validation module 145.

In a certain example, the validation module 145 is configured toautomatically determine an indication of a tissue type at the tissuesite using the received intrinsic electrical signal, and further, toautomatically enable or inhibit electrical energy delivery to the tissuesite using the determined indication of the tissue type. In the exampleof FIG. 3, the user confirmation/override 146 can be configured torequire a physician, user, or other operator, to either confirm oroverride the determination of the validation module 145 before thevalidation module 145 can enable or inhibit electrical energy deliveryto the tissue site. In certain examples, the user confirmation/override146 is configured to enable or inhibit electrical energy delivery to thetissue site independent of, or in conjunction with, the validationmodule 145 using physician, user, or other operator input orinformation.

In certain examples, the user confirmation/override 146 communicateswith an external programmer, or other communication device, for operatorinput. In certain examples, the user confirmation/override 146 isconfigured to use such operator input only during one or more specificoperating modes, e.g., during initial programming after implantation, orduring normal operation.

FIG. 4 is a block diagram illustrating generally an example of a system400 including an implantable medical device 105 and an external device165. The implantable medical device 105 includes an electrical energydelivery circuit 115, an intrinsic electrical signal sensing circuit125, a terminal 135, a validation module 145, and a notification module155. The external device 165 can be implemented using any device capableof communicating with an implantable medical device 105, e.g., anexternal programmer or remote patient management system such as theLATITUDE system available from the assignee of the present patentapplication. The external device 165 can incorporate certainfunctionality that is shown in FIG. 4, for illustrative purposes, asbeing located in the implantable medical device 105, for example, someor all of the validation module 145 or the notification module 155 couldbe implemented in the external device 165.

In the example of FIG. 4, the notification module 155 generally notifiesa physician, user, or other operator of the determined indication oftissue type, or the determined tissue type, by the validation module145. In certain examples, the notification module 155 can send to theexternal device 165 any information received by or sent by thevalidation module 145, e.g., received intrinsic electrical signals froma tissue site from the intrinsic electrical signal sensing circuit 125,determinations of tissue type from the validation module 145, or“enable” or “inhibit” signals sent to the electrical energy deliverycircuit 115.

FIG. 5 is a block diagram illustrating generally an example of a system500 including an implantable medical device 105. The implantable medicaldevice 105 includes an electrical energy delivery circuit 115, anintrinsic electrical signal sensing circuit 125, a terminal 135, avalidation module 145, and a connectivity module 170.

In the example of FIG. 5, the connectivity module 170 is coupled to theintrinsic electrical signal sensing circuit 125 and the electricalenergy delivery circuit 115, and generally determines an electricalconnectivity (e.g., of the terminal 135) of the implantable medicaldevice 105 to the tissue site In certain examples, the connectivitymodule 170 receives an intrinsic electrical signal from the intrinsicelectrical signal sensing circuit 125. The connectivity module 170 usesthe intrinsic electrical signal to determine the electrical connectivityof the implantable medical device 105 to the tissue site. In certainexamples, the connectivity module 170, upon determining the electricalconnectivity, then enables or inhibits electrical energy delivery to thetissue site using the determined electrical connectivity. This mayinclude, for example, enabling electrical energy delivery if the lead(e.g., the first lead 215 or the second lead 235) is connected, orinhibiting electrical energy delivery if the lead (e.g., the first lead215 or the second lead 235) is not connected. This may also includeenabling or disabling electrical energy delivery based on the indicationof tissue type provided by the validation module 145.

FIG. 6 illustrates generally an example of a method 600 that includesautomatically enabling or inhibiting electrical energy delivery to atissue site by using an indication of the tissue type determined using asensed intrinsic electrical signal at the tissue site.

In the example of FIG. 6, at 605, an intrinsic electrical signal issensed at a tissue site. An intrinsic electrical signal can also includean electrical characteristic, e.g., impedance, voltage, etc. In anotherexample, more than one intrinsic electrical signal is sensed at one ormore than one tissue site. In one example, the intrinsic electricalsignal is sensed using a lead, e.g., the first lead 215 or the secondlead 235. In one example, the first lead 215 is configured to sense anintrinsic cardiac signal, and the second lead 235 is configured to sensean intrinsic neural signal. In other examples, one or more than oneintrinsic cardiac signal is sensed, or one or more than one intrinsicneural signal is sensed.

At 610, an indication of tissue type at the tissue site is determined.The indication of tissue type can be determined by sensing eithercardiac or neural activity in the intrinsic electrical signal sensed atthe tissue site. Cardiac activity typically includes activity indicativeof a depolarization, repolarization, or cyclical variation of the heart,which usually involves a generally well-defined frequency range,typically varying from 10 Hz to 120 Hz. In contrast, neural activitytypically includes activity more akin to “white noise”, usually ofbroader frequency range, and generally including more amplitude orfrequency variation.

One or more other distinctive characteristics can be used to distinguishtissue types. One such characteristic is impedance measurement of thetissue at the tissue site. Generally, cardiac tissue can have adifferent impedance measurement than neural tissue. The desired tissuesite may have a known impedance range, e.g., the impedance may bedetermined upon implantation. In one example, if the impedance measuredat the tissue site is not the expected value, the validation module 145will not enable electrical energy delivery to that tissue site. Anothercharacteristic is signal amplitude at the tissue site. Generally, anintrinsic electrical signal at a cardiac tissue site near the heart willhave a high signal amplitude. In contrast, an intrinsic electricalsignal at a neural tissue site, e.g., at the vagal nerve in the neck,will typically have a lower signal amplitude. In another example, acardiac signal can be present at a neural tissue site, e.g., at a neuraltissue site near the heart. In these examples, though a cardiaccharacteristic can be present at the neural site, the indication oftissue type at the tissue site can still be determined to be that ofneural tissue.

At 615, if the determined indication of tissue type at the tissue siteis determined to be the correct tissue type by the validation module145, then electrical energy delivery is automatically enabled to thetissue site at 620. In certain examples, the electrical energy deliverycircuit 115 is configured to deliver a specific type of energy, e.g., apacing energy or a neural stimulation energy, to a single or more thanone tissue site. In one example, at 615, if, at 610, the determinedindication of tissue type is consistent with the type of tissue that theelectrical energy delivery circuit 115 was configured to deliver energyto, then validation module 145 is configured to automatically enableelectrical energy deliver to the tissue site at 620. At 615, if thedetermined indication of tissue type at the tissue site is notdetermined to be the correct tissue type by the validation module 145,then electrical energy delivery is automatically inhibited to the tissuesite at 625. In one example, if, at 615, if, at 610, the determinedindication of tissue type is not consistent with the type of tissue towhich the electrical energy delivery circuit 115 was configured todeliver energy, then validation module 145 is configured toautomatically inhibit electrical energy delivery to the tissue site at625.

In certain examples of FIG. 6, more than one intrinsic electrical signalis being sensed at more than one tissue site. In an example, at 620,electrical energy delivery to the tissue site is enabled in sequence.Sequence enabling can include enabling electrical energy delivery to afirst tissue site, e.g., enabling electrical energy delivery to anatrial tissue site upon determining a correct atrial tissue siteindication at 615, and then to a second tissue site, e.g., enablingelectrical energy delivery to a left ventricle tissue site upondetermining a correct left ventricle tissue site indication at 615.Sequence enabling can include any combination of tissue site enabling,e.g., atrial, left ventricular, right ventricular, or neural. In certainexamples, one cardiac tissue site can be distinguished from anothercardiac tissue site using one or more distinctive characteristics, e.g.,impedance, amplitude, etc. In another example, validation module 145determines if each determined indication of tissue type at each lead,e.g., the first lead 215 or the second lead 235, is the correct tissuetype before electrical energy delivery is delivered on any lead, e.g.,the first lead 215 or the second lead 235.

FIG. 7 illustrates generally an example of a method 700 includingautomatically enabling or inhibiting electrical energy delivery to atissue site using an indication of the tissue type that is determined bydelivering a test electrical energy to the tissue site and detecting aresponse to the delivered test electrical energy.

In the example of FIG. 7, at 705, an intrinsic electrical signal issensed at a tissue site. At 710, an indication of tissue type at thetissue site is determined. The indication of tissue type can bedetermined using the intrinsic electrical signal sensed at the tissuesite. Alternatively, at 711, a test electrical energy can be deliveredto the tissue site. In certain examples, the test electrical energyincludes a cardiac stimulation or a neural stimulation. The cardiacstimulation or neural stimulation can include a stimulation designed tobe strong enough to cause a stimulation response, but weak enough to notharm the tissue the stimulation is being delivered to. The response tothe test electrical energy can be indicative of the tissue type at thetissue site, e.g., a cardiac contraction. The test electrical energydelivery at 711 is typically of a short duration, configured to eitherdetect a response or the lack of a response. At 712, a test electricalsignal response to the delivered test electrical energy is detected.Thus, at 710, an indication of tissue type at the tissue site can bedetermined using the detected test electrical signal response at 712 tothe delivered test electrical energy at 711.

In an example, at 711, a test electrical energy is delivered to thetissue site, such that the test electrical energy is safe for neuraltissue and sufficient to cause a cardiac response. In certain examples,a test electrical energy of a low amplitude, low frequency, or smallpulse-width is safe for neural tissue and sufficient to cause a cardiacresponse. In one example, a test electrical energy of low amplitude, lowfrequency, or small pulse-width that is safe for neural tissue andsufficient to cause a cardiac response includes a single 4 Volt pulse toa tissue site having an impedance of 1 k Ohms, which delivers roughly 4mA of current to the tissue site. In other examples, more than one pulsecan be delivered with a low repetition rate or small pulse width and canbe safe for neural tissue and sufficient to cause a cardiac response. At712, delivery of the test electrical energy ceases to avoid damage tothe tissue site.

At 715, if the determined indication of tissue type at the tissue siteis determined to he the correct tissue type by the validation module145, then electrical energy delivery is automatically enabled to thetissue site at 720. At 715, if the determined indication of tissue typeat the tissue site is not determined to be the correct tissue type bythe validation module 145, then electrical energy delivery isautomatically inhibited to the tissue site at 725.

FIG. 8 illustrates generally an example of a method 800 includingautomatically enabling or inhibiting electrical energy delivery to atissue site using a automatically determined indication of the tissuetype, including obtaining a user confirmation/override.

In the example of FIG. 8, at 805, an intrinsic electrical signal issensed at a tissue site. At 810, an indication of tissue type at thetissue site is automatically determined, such as by using the intrinsicelectrical signal sensed at the tissue site, or by delivering a testelectrical energy and using a test electrical energy response.

At 815, if the determined indication of tissue type at the tissue siteis determined to be the correct tissue type by the validation module145, then electrical energy delivery is automatically enabled to thetissue site at 820. At 815, if the determined indication of tissue typeat the tissue site is not determined to be the correct tissue type bythe validation module 145, then electrical energy delivery isautomatically inhibited to the tissue site at 825.

However, at 819 and 824, before the validation nodule 145 automaticallyenables or inhibits electrical energy delivery to the tissue site at 820or 825, a user confirmation/override 146 can be required. This wouldrequire either confirmation or override, by a physician, user, or otheroperator, of the determination of the validation module 145 toautomatically enable or inhibit electrical energy delivery to the tissuesite.

FIG. 9 illustrates generally an example of a method 900 includingautomatically enabling or inhibiting electrical energy delivery to atissue site using an automatically determined indication of the tissuetype, including communicating an indication of tissue type to anexternal device.

In the example of FIG. 9, at 905, an intrinsic electrical signal issensed at a tissue site. At 910, an indication of tissue type at thetissue site is determined. The indication of tissue type can bedetermined using the intrinsic electrical signal sensed at the tissuesite. Alternatively, the indication of tissue type can be determinedusing a test electrical energy and a test electrical energy response.

At 913, a notification module 155 communicates the determined indicationof tissue type, from 910, to an external device 165. The external devicecan include a medical device programmer, a user display, or any otherdevice capable of displaying, to a physician, user, or other operator,or storing the determined indication of tissue type.

At 915, if the determined indication of tissue type t the tissue site isdetermined to be the correct tissue type by the validation module 145,then electrical energy delivery is automatically enabled to the tissuesite at 920. At 915, if the determined indication of tissue type at thetissue site is not determined to be the correct tissue type by thevalidation module 145, then electrical energy delivery is automaticallyinhibited to the tissue site at 925.

FIG. 10 illustrates generally an example of a method 1000 includingautomatically enabling or inhibiting electrical energy delivery to atissue site using a determined electrical connectivity to the tissuetype, where the connectivity is determined using a sensed intrinsicelectrical signals at the tissue site.

In the example of FIG. 10, at 1005, an intrinsic electrical signal issensed at a tissue site At 1010, an indication of tissue type at thetissue site is determined. The indication of tissue type can bedetermined using the intrinsic electrical signal sensed at the tissuesite. Alternatively, the indication of tissue type can be determinedusing a test electrical energy and a test electrical energy response.

At 1015, if the determined indication of tissue type at the tissue siteis determined to be the correct tissue type by the validation module145, then electrical energy delivery can be automatically enabled to thetissue site at 1020. At 1015, if the determined indication of tissuetype at the tissue site is not determined to be the correct tissue typeby the validation module 145, then electrical energy delivery can beautomatically inhibited to the tissue site at 1025.

At 1014, an electrical connectivity to the tissue site is determined.The electrical connectivity to the tissue site can be determined byusing the sensed intrinsic electrical signal at the tissue site. In oneexample, an impedance measurement is taken at the tissue site. If asubstantially high impedance is measured, e.g., much higher than anormal tissue impedance, then the terminal 135 may not be coupled to thetissue site.

At 1016, if the terminal 135 is determined to be electrically connectedto the tissue site by the connectivity module 170, then electricalenergy delivery can be automatically enabled to the tissue site at 1020.At 1016, if the terminal 135 is determined to not be electricallyconnected to the tissue site by the connectivity module 170, thenelectrical energy delivery can be automatically inhibited to the tissuesite at 1025.

In one example, at 1020, electrical energy delivery to the tissue sitecan be automatically enabled if either the determined indication oftissue type at the tissue site is determined to be the correct tissuetype by the validation module 145, at 1015, or the terminal 135 isdetermined to be electrically connected to the tissue site by theconnectivity module 170, at 1016. In another example, at 1020,electrical energy delivery to the tissue site can be automaticallyenabled if both the determined indication of tissue type at the tissuesite is determined to be the correct tissue type by the validationmodule 145, at 1015, and the terminal 135 is determined to beelectrically connected to the tissue site by the connectivity module170, at 1016.

In one example, at 1025, electrical energy delivery to the tissue sitecan be automatically inhibited if either the determined indication oftissue type at the tissue site is not determined to be the correcttissue type by the validation module 145, at 1015, or the terminal 135is determined to not be electrically connected to the tissue site by theconnectivity module 170, at 1016. In another example, at 1025,electrical energy delivery to the tissue site can be automaticallyinhibited if both the determined indication of tissue type at the tissuesite is not determined to be the correct tissue type by the validationmodule 145, at 1015, and the terminal 135 is determined to not beelectrically connected to the tissue site by the connectivity module170, at 1016.

FIG. 11 illustrates generally an example of a method 1100 includingenabling a pacing energy or inhibiting a neurostimulation energy if anintrinsic cardiac signal is present, inhibiting a pacing energy if anintrinsic cardiac signal is not present, enabling a neurostimulationenergy or inhibiting a pacing energy if an intrinsic neural signal ispresent, and inhibiting a neurostimulation energy if an intrinsic neuralsignal is not present.

In the example of FIG. 11, at 1105, an intrinsic electrical signal issensed at a tissue site. At 1110, if the intrinsic electrical signalsensed at 1105 includes an intrinsic cardiac signal, then a pacingenergy is enabled or a neurostimulation energy is inhibited at 1115.Alternatively, any cardiac stimulation can be enabled, or any neuralstimulation can be inhibited at 1115. At 1110, if the intrinsicelectrical signal sensed at 1105 does not include an intrinsic cardiacsignal, then a pacing energy is inhibited at 1120. Alternatively, anycardiac signal can be inhibited at 1120.

At 1125, if the intrinsic electrical signal sensed at 1105 includes anintrinsic neural signal, then a neurostimulation energy is enabled or apacing energy is inhibited at 1130. Alternatively, any neuralstimulation can be enabled, or any cardiac stimulation can be inhibitedat 1130. At 1125, if the intrinsic electrical signal sensed at 1105 doesnot include an intrinsic neural signal, then a neurostimulation energyis inhibited at 1135. Alternatively, any neural stimulation can beinhibited at 1135.

In the examples of FIGS. 6-11, various examples, including sensing anintrinsic electrical signal at a tissue site, determining an indicationof tissue type at the tissue site, or automatically enabling orinhibiting electrical energy delivery to the tissue site, are disclosed.It is to be understood that these examples are not exclusive, and can beimplemented either alone or in combination, or in various permutationsor combinations.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. Many other embodiments will be apparent to those of skill inthe art upon reviewing the above description. The scope of the inventionshould, therefore, be determined with reference to the appended claims,along with the full scope of equivalents to which such claims areentitled. In the appended claims, the terms “including” and “in which”are used as the plain-English equivalents of the respective terms“comprising” and “wherein.” Also, in the following claims, the terms“including” and “comprising” are open-ended, that is, a system, device,article, or process that includes elements in addition to those listedafter such a term in a claim are still deemed to fall within the scopeof that claim. Moreover, in the following claims, the terms “first,”“second,” and “third,” etc. are used merely as labels, and are notintended to impose numerical requirements on their objects.

The Abstract is provided to comply with 37 C.F.R. §1.72(b), whichrequires that it allow the reader to quickly ascertain the nature of thetechnical disclosure. It is submitted with the understanding that itwill not be used to interpret or limit the scope or meaning of theclaims. Also, in the above Detailed Description, various features may begrouped together to streamline the disclosure. This should not beinterpreted as intending that an unclaimed disclosed feature isessential to any claim. Rather, inventive subject matter may lie in lessthan all features of a particular disclosed embodiment. Thus, thefollowing claims are hereby incorporated into the Detailed Description,with each claim standing on its own as a separate embodiment.

What is claimed is:
 1. A system comprising: an electrical energydelivery circuit configured to deliver neurostimulation energy; a signalsensing circuit configured to sense an electrical characteristic of atleast one tissue site; a validation module, coupled to the electricalenergy delivery circuit and the signal sensing circuit, configured todetermine an indication of a cardiac tissue type at the at least onetissue site using the sensed electrical characteristic; and a controlcircuit configured to inhibit the electrical energy delivery circuitfrom delivering the neurostimulation energy at least in response to theindication of the cardiac tissue type.
 2. The system of claim 1, whereinthe signal sensing circuit is configured to sense a tissue impedance. 3.The system of claim 1, comprising one or more leads configured to couplethe electrical energy delivery circuit and the signal sensing circuit tothe at least one tissue site via at least one electrode incorporatedonto the one or more leads.
 4. The system of claim 1, wherein thevalidation module is further configured to determine an indication of aneural tissue type, and the control circuit is configured to enable theelectrical energy delivery circuit to deliver the neurostimulationenergy at least in response to the indication of the neural tissue type.5. The system of claim 1, wherein the validation module is configured todetermine the indication of the cardiac tissue type including a locationof the at least one tissue site.
 6. The system of claim 1, wherein thevalidation module comprises a user input device enabling a user toconfirm or override the indication of the cardiac tissue type, andwherein the control circuit is configured to inhibit the electricalenergy delivery circuit from delivering the neurostimulation energy atleast in response to the confirmed indication of the cardiac tissuetype.
 7. The system of claim 1, wherein the electrical energy deliverycircuit is configured to deliver a test electrical energy to the atleast one tissue site, the signal sensing circuit is configured todetect a response to the test electrical energy, and the validationmodule is configured to determine the indication of the cardiac tissuetype using the detected response to the test electrical energy.
 8. Thesystem of claim 7, wherein the test electrical energy includes a cardiacpacing energy.
 9. The system of claim 7, wherein the test electricalenergy includes a neurostimnulation energy.
 10. The system of claim 1,further comprising a connectivity module coupled to the signal sensingcircuit and the electrical energy delivery circuit, the connectivitymodule configured to determine an electrical connectivity between theelectrical energy delivery circuit and the at least one tissue site,wherein the control circuit is configured to inhibit the electricalenergy delivery circuit using the determined electrical connectivity.11. The system of claim 10, wherein the control circuit is configured toinhibit the electrical energy delivery circuit from delivering theneurostimulation energy in response to a determination of no electricalconnectivity between the electrical energy delivery circuit and the atleast one tissue site.
 12. A system, comprising: means for deliveringneurostimulation energy; means for sensing an electrical characteristicat at least one tissue site; means for determining an indication of acardiac tissue type at the at least one tissue site using the sensedelectrical characteristic; and means for inhibiting delivery ofneurostimulation energy to the at least one tissue site in response tothe determination of the indication of the cardiac tissue type.
 13. Thesystem of claim 12, wherein the means for sensing the electricalcharacteristic includes means for sensing a tissue impedance.
 14. Thesystem of claim 12, wherein the means for determining the indication ofthe cardiac tissue type includes means for determining a location of theat least one tissue site.
 15. The system of claim 12, furthercomprising: means for determining an indication of a neural tissue type;and means for enabling delivery of neurostimulation energy to the atleast one tissue site in response to the determination of the indicationof the neural tissue type.
 16. The system of claim 12, furthercomprising means for obtaining a user input to confirm or override theindication of the cardiac tissue type determined using the sensedelectrical characteristic, wherein the means for inhibiting the deliveryof neurostimulation energy includes means for inhibiting the delivery ofthe neurostimulation energy in response to the confirmed indication ofthe tissue type.
 17. The system of claim 12, fiirther comprising meansfor delivering a test electrical energy to the at least one tissue siteand detecting a response to the test electrical energy, wherein themeans for determining the indication of the cardiac tissue type includesmeans for using the detected response to the test electrical energy todetermine the indication of the cardiac tissue type.
 18. The system ofclaim 17, wherein the means for delivering the test electrical energyincludes means for delivering a cardiac pacing energy.
 19. The system ofclaim 17, wherein the means for delivering the test electrical energyincludes means for delivering a neurostimulation energy.
 20. The systemof claim 12, further comprising means for determining an electricalconnectivity to the at least one tissue site, wherein the means forinhibiting the delivery of neurostimulation energy includes means forinhibiting the delivery of neurostimulation energy using the determinedelectrical connectivity.